Journal of Ecology and the Natural Environment Vol. 4(13), pp. 333-343, October, 2012 Available online at http://www.academicjournals.org/jene DOI: 10.5897/JENE12.047 ISSN 2006 – 9847 ©2012 Academic Journals Full Length Research Paper Woody species composition, structure and diversity of vegetation of Kalfou Forest Reserve, Cameroon Moksia Froumsia1*, Louis Zapfack2, Pierre Marie Mapongmetsem3 and Bernard-Aloys Nkongmeneck2 1Department of Agriculture, Livestock and Derived Products, Higher Institute of the Sahel, University of Maroua, Box 46 Maroua, Cameroon. 2Department of Plant Biology, Faculty of Sciences, University of Yaoundé I, Box 812 Yaoundé, Cameroon. 3Department of the Biological Sciences, Faculty of Sciences, University of Ngaoundéré, Box 454 Ngaoundéré, Cameroon. Accepted 13 September, 2012 Studies were carried out in the Kalfou Forest Reserve to make an assessment of the flora diversity and to develop preservation guidelines facing the increase in its degradation. The composition of woody species, structure, diversity, density, dominance, frequency of species and family importance value were described and evaluated in all the forest reserve area. A total of 86 species representing 58 genera and 28 families of woody species were identified. The families of Combretaceae, Fabaceae- caesalpinioideae and Fabaceae-mimosoideae were the most abundant families in the Kalfou Forest Reserve. The density of stems ≥ 10 cm circumference and the basal area were higher in the Doulouk and Gonoray parts of the reserve. The distribution of stems of the main species in classes of circumference had shown a reverse “J” shaped curve. The number of stems of shrubs species was important and strongly influenced globally the diameter and the height of the stems which were lower. Species diversity was a slight difference among the various parts of the forest reserve area. The species abundance showed that, 20% of the species were infrequent. The dynamic of renewal of species were ensured by the weakly regeneration: seedling (2.03%), rejection issues (41.97%) and the death rate of individual species was 8.02%. Disturbances and the vulnerability of the seedlings did not ensure species sustainability. Preservation systems and adequate management were therefore recommended in order to ensure sustainable management of the Kalfou Forest Reserve resources. Key words: Biodiversity, preservation, forest reserve, sustainability. INTRODUCTION Following the Rio Earth Summit in 1992, the world However, the protected areas, as a means of summit on sustainable improvement in Johannesburg in preservation and management of biodiversity, share their 2002 and that of the parks of the IUCN in Durban in 2003 riches biodiversity and the diversity of their products which reaffirm the main aspects of the preservation of could contribute to the reduction of poverty in these areas biodiversity and the negative assessments of actions of (Anonymous, 2009; Galindo, 2010). Nevertheless, they preservation of biodiversity in the world, were made. face a lot of pressure from human as well as natural phenomenon to ensure sustainable improvement of the resources (Aubertin and Vivien, 1998). These factors dangerously threaten the preservation and management; *Corresponding author. E-mail: [email protected]. Tel: subsequently, strongly cause the regression of the side of (+237) 77 35 91 30. protected areas (Brunner et al., 2001; Ervin, 2003b). The 334 J. Ecol. Nat. Environ. Kalfou Forest Reserve is one of the mainly protected following trails created by firewood cutters and grazing, to sample areas in the Far-North region-Cameroon. It is for the inventory of woody species (Figure 1). These different parts characterized by relatively poor ecosystems and had the same ecological characteristics, except the intensity of human activities (cutting, grazing and bush fire) which differs submitted to human disturbances such as the cutting among others. The inventory was carried out at the end of the rainy down of flora for fuel, construction materials and poles, season and at the middle of the dry season when species could furniture, the harvesting of non timber forest products, easily be identified, transected easily and assessed with regard to medicines, the overgrazing and bush fires (Wafo, 2009; the regeneration capacity of species by rejections and seeds Madi et al., 2003). These factors induce a remarkable germination. A total of 48 transects of 2000 × 20 m were marked out over an area of 192 ha in the forest reserve area: ten in the degradation of flora, leading to their scarcity and the Barodewol, Doulouk, Gonoray and Saroudja parts and eight in the alteration of the ecosystems as well as a significant loss Hadande part. In order to evaluate the renewal capacity of woody of biodiversity (Khresat et al., 1998; Darkoh, 2003). In this species, plots of 50 × 50 m were realized at an opened field as well regard, it will be essential to have reliable and relevant as covered field for the determination of young plants inside ecological and environmental data in order to supervise transects randomly. Transects and plots were then systematically in future, factors responsible of the biodiversity extinction surveyed, and all woody species with circumference ≥ 10 cm were enumerated and identified. Number of stems, cutting trees, in this protected area. The problem faced is that of individual dead trees, rejections from and all young plants of the preservation and the sustainable management of woody species were also enumerated. The circumference were resources in the Kalfou Forest Reserve which is also measured at 0.3 m from the soil using a measuring tape and subjected to a high degradation which con-sequently is the height of the largest stem using a graduated pole or clinometers unable to meet the objectives for which it was created. in for the tallest trees. According to the investigations, a list of main spite of the significant number of studies (Fotsing et al., species were drawn up, the number of stems, death rate and regeneration capacity were recorded. All trees or shrubs 2003; Wafo and Huynh, 2009), carried out based on land encountered in the field were grouped according to species; while sat images to provide first basic elements for the those which are not well-known were identified in the national characterization of the landscapes of the Far-North herbarium in Yaoundé-Cameroon. The species composition of the Region, Cameroon, no field study was conducted different parts was described using the following parameters. specifically on the evaluation of woody species in the 1. Relative dominance = (total basal area for a species/total basal Kalfou Forest Reserve. The main objective of this area of all species) × 100. research is to create awareness on the Kalfou Forest 2. Relative density = (number of individuals of a species/total Reserve for it sustainable management. The specific number of individuals) × 100. objectives include: (1) the determination of woody 3. Relative frequency = (frequency of a species/sum of all species in the Kalfou Forest Reserve; (2) the evaluation frequencies) × 100. of the diversity of woody species and structure, and (3) 4. Relative diversity = (number of a species in a family/total number of species) × 100. the evaluation of the dynamic regenerations of woody 5. The importance value index (IVI) = relative dominance + relative species. density + relative frequency. 6. The family importance value (FIV) = relative dominance + relative MATERIALS AND METHODS density + relative diversity. Study area The frequency of a species is defined as the number of transects (2000 × 20 m) in which the species occur. This study was carried out in the Kalfou Forest Reserve, located The theoretical range for relative dominance, relative frequency, between 10°17 ' and 10°28' latitude, 15°06' and 15°21' longitude relative density and relative diversity is 0 – 100%, so that IVI of and at an altitude of 250 m (Figure 1). The Sudano-Sahelian species and FIV may vary between 0 and 300%. Structural climate is characterized by two different seasons: the dry season characteristics (stem density, basal area, and circumference class which lasts for 8 months (ranging from October to May) and the distributions) were calculated for each part for all individuals with a short rainy season which lasts for 4 months (ranging from June to circumference ≥ 10 cm belonging to the most important species. To September). The average (± standard deviation (SD)) annual compare diversity within each part, the Margalef’s index, Simpson’s rainfall from1970 to 2010 was evaluated 748 ± 120 mm, while the index, Shannon’s measure of evenness, Shannon-Wiener’s mean annual temperature was 28°C. The characteristic of flora in information index and Diversity index (D) were calculated. These the region is that of steppes with thorn-bush made up of shrubby indices are widely employed to measure biological diversity savannas with a very irregular herbaceous floor cover dominated by (Magurran, 2004). The dynamic of renewal species was evaluated thorn-bushes, strongly degraded as the result of human actions from trees death rate, regeneration rate such as seeds germination (Letouzey, 1985). The economic activities of the bordering and rejections. XLStat 8.4 was used for data analysis. populations are mainly extensive and subsistence agriculture, extensive livestock, exploitation of resources and small trade. RESULTS Data collection Species composition According to the information gotten from the